JPS6323365B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an engine oil level detection device;
In particular, there is a ring-shaped float that moves up and down depending on the oil level, and a first
A detector consisting of a magnet and a reed switch that passes vertically through the center of the float is installed in the oil reservoir at the bottom of the engine body, and a flywheel that is integrally fixed to the crankshaft has an ignition The present invention relates to an oil level detection device for an engine to which a second magnet is fixedly installed.

Conventionally, in such oil level detection devices,
It is recognized that the negative effect on the detector due to the leakage magnetic flux of the second magnet is caused by the magnetic path of the leakage magnetic flux being formed by the steel plate cover that covers the cooling fan provided on the flywheel. It wasn't much of an issue. However, if the cover is made of synthetic resin or made thinner in order to reduce the weight of the engine, the influence of the leakage magnetic flux of the second magnet becomes large, and depending on the relative position of the detector and the flywheel, the second magnet The detector may malfunction due to magnetic flux leakage from the magnet.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine oil level detection device that prevents malfunction of the detector due to leakage magnetic flux of the second magnet provided in the flywheel. do.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. First, in FIG. 1, an engine main body 1
A piston (not shown) sliding inside the cylinder 2 of
A crankshaft 4 connected via a connecting rod 3 to
It is rotatably supported by a crankcase 7 via bearings 5 and 6, and a flywheel 9 is integrally fixed to one end of the crankshaft 4 together with a cooling fan 8. An oil reservoir 10 is formed in the lower part of the engine body 1, that is, in the lower part of the crankcase 7.In order to detect the oil level L in this oil reservoir 10, a ring-shaped float 11, a first magnet 12, and a reed switch 13 are connected. A detector 14 is disposed in the oil sump 10 below the crankshaft 4. On the other hand, a second magnet 15 is located at a certain position along the circumferential direction of the flywheel 9.
An ignition device unit 17 is installed in the engine body 1 and is operated by the magnetic force of the second magnet 15 to cause the spark plug 16 to generate a spark.

In FIG. 2, the casing 18 of the detector 14
is basically formed into a bottomed cylindrical shape with an open lower end, and a pair of mounting arms 19 and 20 integrally formed with the casing 18 allow the crankshaft 5 (see Fig. 1) to be attached to the crankshaft 5 (see Fig. 1). Crankcase 7 below
(See Figure 1). Casing 18
A support cylinder 21 is suspended from the top at the center of the support cylinder 21. A reed switch 13 extending vertically is provided inside the support cylinder 21, and a pair of lead wires 22 are connected to both contacts of the reed switch 13, respectively.
23 is pulled out through a guide tube 24 extending laterally from the top of the casing 18. A retaining member 26 is press-fitted into the open end of the casing 18, which is basically cross-shaped as shown in FIG. A stopper projection 27 is provided protruding from the upper end of the raised portion 25 . Inside the casing 18 is a ring-shaped float 1 concentrically surrounding the support tube 21.
1 is housed in the float 11, and the float 11 moves up and down according to the level of oil flowing through the retaining member 26 and flowing into the casing 18, and the float 11 is prevented from falling off from the casing 18. This is blocked by member 26. Also float 11
A ring-shaped first magnet 12 is embedded in the inner peripheral surface of the reed switch 1.
3 opens and closes.

That is, in FIG. 3, when the float 11 and the first magnet 12 rise above the open/close position of the reed switch 13 as shown in FIG. No magnetic path is formed through the switch 13, and the reed switch 13 remains open. Further, as shown in FIG. 3b, when the float 11 and the first magnet 12 come to positions corresponding to the open/close positions of the reed switch 13, the reed switch 13 is closed by the magnetic force of the first magnet 12, and the reed switch 13 is closed. A magnetic path is formed through the In this way, the reed switch 13 opens and closes, but the float 11 and the first magnet 1
2 is located below the opening/closing position of the reed switch 13 and the reed switch 13 is opened.
This prevents it from falling below the set position.

A protrusion 28 is provided on the upper surface of the float 11, and this protrusion 28 and the stopper protrusion 27 of the retaining member 26 cause the upper and lower surfaces of the float 11 to come into close contact with the upper part of the casing 18 and the retaining member 26. This prevents the float 11 from malfunctioning due to the close contact.

In FIG. 4, according to the present invention, the lower magnetic pole of the first magnet 12 and the lower magnetic pole of the second magnet 15
The magnetic poles on the outer side along the radial direction of the flywheel 9 are set to be the same pole. That is, if the float 11 is arranged such that the lower side of the first magnet 12 is the north pole and the upper side is the south pole,
The second magnet 15 is embedded in the flywheel 9 so that the outer side along the radial direction of the flywheel 9 is a north pole and the inner side is a south pole. Moreover, in order to avoid mistakes in the installation direction of the float 11, a mark is formed on the float 11 to indicate the direction in which the first magnet 12 is buried.In this embodiment, the protrusion 28 of the float 11 is used as the mark. There is.

Next, to explain the operation of this embodiment, when the second magnet 15 of the flywheel 9, which rotates integrally with the crankshaft 4, comes to the lower position as shown in FIG. The direction of the magnetic field caused by the first magnet 12 matches the direction of the magnetic field caused by the first magnet 12 at the position of the reed switch 13, and the magnetic force of the first magnet 12 is strengthened by the second magnet 15. Therefore, the reed switch 13 operates reliably in accordance with the vertical movement of the float 11 and the first magnet 12. On the other hand, if such consideration is not taken, the magnetic force of the first magnet 12 is weakened by the second magnet 15, and even when the oil level L is below the set level, the reed switch 13 may not operate properly.

In the above embodiment, the lower side of the first magnet 12 is the N pole, and the magnetic pole of the second magnet 15 on the outer side along the radial direction of the flywheel 9 is the N pole. Needless to say, it's a good thing.

As described above, according to the present invention, the detector is arranged below the crankshaft, and the lower magnetic pole of the first magnet and the outer magnetic pole along the radial direction of the flywheel of the second magnet are different from each other. , are set to have the same polarity, so when the second magnet moves downward in accordance with the rotation of the flywheel and exerts the greatest influence on the first magnet, the magnetic force of the first magnet is strengthened by the second magnet. Therefore, the reed switch operates reliably in accordance with the vertical movement of the float and the first magnet, and the oil shortage can be reliably displayed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall longitudinal sectional side view, FIG. 2 is an enlarged longitudinal sectional view of the detector, and FIG. 2A is a plan view of the retaining member shown in FIG. 2.
Figure 3 is a diagram for explaining the operation of the detector, where Figure 3a shows when the oil level is sufficiently high, Figure 3b shows when the oil level has decreased, and Figure 4 shows when the oil level is low.
The figure shows the magnetic pole arrangement of the first magnet and the second magnet. 1... Engine body, 4... Crankshaft, 9... Flywheel, 10... Oil reservoir, 11... Float,
12...first magnet, 13...reed switch,
14...Detector, 15...Second magnet, L...Oil level.

Claims (1)

[Claims] 1 A ring-shaped float that moves up and down depending on the oil level, and a first ring-shaped float buried in the inner peripheral surface of the float.
A detector consisting of a magnet and a reed switch placed vertically in the center of the float is installed in the oil reservoir at the bottom of the engine body. In an engine oil level detection device in which a second magnet is fixedly installed, the detector is arranged below the crankshaft, and the lower magnetic pole of the first magnet and the flywheel of the second magnet are connected to each other. An engine oil level detection device characterized in that the outer magnetic pole along the radial direction is set to the same pole.